conformationally constrained 10-memberedcyclic diamide was designed and synthesized. Conformational analysis suggested that the 9-membered ring formation was preferred to the direct formation of 10-membered ring. On the basis of the prediction, lactonization of 9-membered lactone, followed by intramolecular ester–amide transformation afforded the desired 10-memberedcyclic diamide.
Sequential Asymmetric Hydrogenation of Symmetric Bis-Cinnamic Acid Derivatives: Syntheses of the <i>C</i><sub>2</sub>-Symmetric Core Units of HIV Protease Inhibitors